Beam splitters are used in a wide variety of photonics applications to separate or combine optical energy. Beam splitters use a partially reflective surface to reflect a portion of incident light while allowing the remainder to be transmitted through the beam splitter. However, many beam splitter configurations use beam-splitting coatings deposited on a relatively thick substrate. This thick substrate can lead to stray reflections, ghosting, beam offsets, undesirable optical interference, and other issues.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.